1. Field of the Invention
The invention generally relates to a geographic based communications service and, more particularly, is concerned with a system and method for determining the approximate location of mobile users of portable computing devices who are in the vicinity of wireless local area network access points.
2. Description of the Related Art
As technology improvements result in smaller, lighter and more portable computing devices (PCDs), a wide variety of new applications and users will emerge. Mobile users will not only operate such devices in stand alone mode, but will also desire the ability to send and receive information through such devices while at virtually any location. The need to communicate will arise in circumstances where hard-wired links may not be readily available or practical or when the mobile user cannot be reached immediately. Moreover, as a result of the user being mobile, the precise location of the PCD is often variable or not determined. As used herein, xe2x80x9cMUxe2x80x9d is an abbreviation for xe2x80x9cmobile user of a portable computing devicexe2x80x9d. Similarly, the plural, xe2x80x9cMUsxe2x80x9d is an abbreviation for xe2x80x9cmobile users of portable computing devicesxe2x80x9d.
Conventional communication systems for computing devices are not equipped to handle such communication scenarios. Commercially available PCDs are generally equipped with industry standard interface ports for driving a peripheral device such as a printer, a plotter, or a modem. While operating in an unknown, remote location not connected to a network, a MU may be unaware of messages waiting for him. In addition, conventionally, the MU may need to wait until reaching an office or other place with appropriate equipment to receive such messages and to transmit or print documents or other information prepared by the MU on his portable computing device.
By way of example and not limitation, one type of MU is the traveler who passes through airports or similar mass transit centers (e.g., subway commuters), uses ground transportation, and stays in a hotel. In a typical scenario, a traveler may use a portable computing device to perform calculations or prepare documents during an airplane flight. Simultaneously, associates may leave messages for the traveler on a network. In conventional systems, the traveler""s work product and messages destined for the traveler are not available until the traveler arrives at a location where a wired connection to the traveler""s network is available.
A further example of inefficiencies for the traveler concerns travel arrangements themselves. After arriving at an airport, the traveler proceeds to a car rental desk or to some other transportation location. The traveler typically waits in line while the car rental agency inquires about automobile preference, driver""s license, method of payment, type of insurance required, etc. Having experienced some delay, the traveler is now on his way to a business location or hotel. Upon arriving at a hotel check-in/registration desk, the traveler often experiences further delay waiting in line and providing the check-in clerk with routine information such as address, length of stay, type of room desired, method of payment, etc. In addition, the traveler may need to call back to his office to check for voice-mail messages, thereby incurring further delays. While accessing databases for information about the traveler, where his preferences and requirements may reduce such delays, a common characteristic is that the pending arrival or presence of the traveler is not known to those who may act in advance. Further, conventional systems cannot generally locate a mobile user of a portable computing device and take advantage of that information to reduce the time required to complete routine activities or to provide the traveler options that may enhance the traveler""s productivity.
In another example, when a user dials a telephone number to an automatic teller machine (ATM) locator, the user is prompted to key in his area code and exchange prefix. The locator system then identifies one or more ATMs within the user""s area. However, the system requires the user to call in and cannot locate the user any more accurately than the telephone exchange area. Thus, the user may be advised of an ATM quite a physical distance from the user""s location.
In addition, it is desirable to be able to provide information, such as advertising or other content, to a MU when the information is based on a location of the PCD within a geographic area. It is also desirable to provide information to a MU based on a geographic location of the PCD in combination with demographic information regarding the MU or past transactions of the MU. Information provided to an MU may also be further tailored to an approximate location of the PCD. For instance, using the ATM example above, a content provider may be able to direct a user of a PCD to the nearest ATM machine based on the precise location of the user.
U.S. Pat. No. 5,835,061 discloses a geographic-based communication service system which comprises a plurality of access points which are operable to communicate with PCD""s of mobile users. The geographic location of the access point is known, and when an access point detects a PCD of a user, the access point can provide its geographic location, thus indicating the approximate location of the user. However, since the known geographic location of the access point is used as an indication of the location of the user, the access point or the communications network system can only detect the location of the user within the granularity of the range of the access point, i.e., the PCD of the user may be anywhere within the range of the access point. This may not provide sufficient granularity to provide certain geographic-based services to the user.
Therefore, a new geographic-based communication service is desired which can more precisely identify the geographic location of users.
In one embodiment, the present invention comprises a geographic based communications service system. The geographic-based communications service system includes a network and a plurality of access points connected to the network. The access points may be arranged at known locations in a geographic region. One or more service providers or information providers may be connected to the network to provide services or information on the network. As used herein, the term xe2x80x9cservice providerxe2x80x9d is intended to include goods providers, information providers, and/or service providers.
A mobile user (MU) may use a portable computing device (PCD) to connect to the network and access information or services from the network. The PCD of the mobile user may connect to an access point in a wireless fashion. The PCD may optionally be configured to transmit identification information indicating the identity of the mobile user. Each of the plurality of access points may be configured to independently communicate with a PCD and may also be configured to receive the identification information indicating the identity of the user of the PCD.
When a PCD of a user is in proximity to a first access point and communicates with the first access point, the first access point may determine the geographic location of the PCD and transmit information regarding the geographic location of the PCD to one or more providers on the network. Thus, the first access point is operable to transmit the information regarding approximate geographic location of the PCD, not just the known geographic location of the first access point. This allows improved geographic-based services to be provided to the user.
In the preferred embodiment, one or more access points may include location circuitry. The location circuitry may be configured to perform one of various methods used to determine the geographic location of PCDs of users. Each access point having the location circuitry may thus be operable to detect the location of a user, (i.e., the PCD of a user), with a granularity greater than simply the known geographic location of the access points with which the PCD is communicating. In one embodiment, an access point may communicate with the PCD in a wireless manner in a first geographic area of the access point, wherein the first geographic area is the range of the access point, and the access point may determine a geographic location of the PCD in a second smaller geographic area within the first geographic area. In other words, the access point may determine the geographic location of the PCD with more granularity than the range of the access point.
An access point may use one of several different methods to determine the geographic location of the PCD. The geographic location of the PCD may be determined with a fairly high degree of precision, using one or more access points and one or more of several different techniques.
In one embodiment, the location circuitry may perform signal strength measurements of signals transmitted to the access point by the PCD. The received signal strength may then be compared to the transmitted signal strength, allowing for a determination of the approximate distance between the access point and the PCD. This approximate distance may be used to determine an approximate region in which the user may be located, e.g., a concentric ring region centered around the access point.
The location circuitry may instead or also allow an access point to determine the bearing of an incoming signal (i.e. the direction from which. the transmitted signal originated). An approximate location of a PCD may then be determined by using the bearing information, or by combining the bearing and distance information.
In another embodiment, two or more access points may be used in conjunction with each other to determine the bearing of an incoming signal using triangulation techniques. In this embodiment, each access point involved in the triangulation may individually determine a distance to the PCD. Since the access points involved are located at a fixed distance from each other, the location of the PCD may be determined using standard triangulation techniques.
Distance from an access point may also be determined via the use of data packets including time stamps. When a mobile user carrying a PCD enters a geographic region for a given access point, it""s presence may be detected by the access point. After synchronizing clocks with the PCD, the access point may then transmit a first data packet which includes a time stamp. After receiving the data packet, the PCD may respond by transmitting a second data packet back to the access point. The second data packet may include the original time stamp, and may also include a second time stamp indicating the time at which the first data packet was received. The access point may then calculate the distance to the PCD based on the round trip time of the signal, or based on the one-way transit time of the signal.
In some situations, particularly if the PCD has a heavy processing workload, there may be a delay in responding to the first data packet from the access point. In such cases, the second data packet transmitted by the PCD may include a third time stamp which may indicate the time of transmission of the second data packet. Upon receiving the second data packet, the access point may then assign a fourth time stamp, and calculate the distance based on the difference between the third and fourth time stamps.
Thus, in one embodiment, a respective access point determines a relative geographic location of the PCD relative to the access point. The access point, or a service provider, may then determine the geographic location of the PCD using the known geographic location of the access point and the relative geographic location of the PCD relative to the access point. This may be accomplished using map information that is based on the known geographic location of the access point.
The access point may provide geographic-based services to a user of the PCD based on the information regarding the geographic location of the PCD. Alternatively, the access point may provide information regarding the geographic location of the PCD to a service provider, and the service provider may then provide geographic-based services to a user of the PCD based on this information.
As noted above, the access point may determine information regarding the geographic location of the PCD. The information regarding geographic location of the PCD may involve information regarding one or more vendors or vendor locations that the PCD is located in or proximate to. In one embodiment, a memory coupled to the network, such as in the access point, stores map information including the first geographic area of the access point. The system, e.g., a network device or the access point, may then determine the proximity of the PCD to a vendor using the map information and the geographic location of the PCD. Thus, the access point may use the geographic location of the PCD to determine a proximity of the PCD to one or more vendors. Stated another way, the access point may determine a vendor location of a plurality of possible vendor locations in which the PCD is located or proximate to. The information regarding the geographic location of the PCD thus may include information regarding the PCD""s proximity to vendors or vendor locations. The geographic information provided to a PCD may include graphical information to illustrate to its user the approximate location of a PCD within a mall, airport, or other facility. In some embodiments, geographic information may be presented to a PCD as a floor plan of a mall, airport, or other facility, or as a map of a city or region.
Geographic-based services may be provided to a user of the PCD based on the information regarding the geographic location of the PCD. For example, where the user of the PCD is determined to be physically located proximate to a first vendor, then advertising information corresponding to the first vendor may be provided to the PCD. The geographic-based information provided to the PCD may originate from a service provider or from the access point itself. The information provided to the PCD may be any of various types. The access point may transmit various information to the PCD, wherein the information is dependent upon the geographic location of the PCD and may also be dependent upon demographic information of the user of the PCD.
Other types of geographic-based services may be provided to the user. For example, the access point may transmit the geographic location of the PCD to a memory of the PCD, thereby advising the PCD of its location. Also, the access point may provide directions to a specified location responsive to a query from the PCD, wherein the directions may be based at least in part upon the geographic location of the PCD. Further, the access point may determine a direction of motion of the PCD based on two or more determinations of the geographic location of the PCD over a period of time.
Thus the geographic location information may be useful to both the mobile user and service providers, e.g. content and information providers, coupled to the network. For example, if an access point locates a PCD near a bookstore in an airport, the network may respond by informing the user of a promotion by the bookstore. Similarly, a user of a PCD may query the network for directions to a specific location, such as a food court, a restroom or an ATM machine. The network may then determine directions based on the current location of the PCD. One or more access points may also be used to determine a direction of motion of the user of the PCD, and thus provide feedback to the user while moving to the target location of the query.